1. Field of the Invention
The present invention relates to a printing apparatus and a print timing control method, and more specifically to print timing control in printing while moving a print head.
2. Description of the Related Art
As one mode for controlling a print timing in a printing apparatus which performs printing while moving a print head, there is provided a printing apparatus that detects information about a moving speed of the print head by an encoder or the like and controls a print timing based on the information. The printing apparatus which performs printing not only in constant-speed control but also in acceleration/deceleration control performs print timing control according to a variable speed so that a desirable print position is obtained even when the speed of the print head is variable. Furthermore, the moving speed of the print head may change for some reason even in the constant-speed control, and thus the printing apparatus performs the print timing control in response to the speed variation.
Japanese Patent Laid-Open No. 2007-118425 discloses estimating for each detection cycle of an encoder a moving speed of a cycle by using a moving speed obtained in a previous cycle and determining a print timing of the cycle based on the estimation. More specifically, an estimated speed of a cycle is set based on a result obtained by subtracting a difference between the detected speed of the last cycle but one and the detected speed of the last cycle from the detected speed of the last cycle, and a print timing is controlled based on the estimated speed.
However, as disclosed in Japanese Patent Laid-Open No. 2007-118425, in a mode that the moving speed of the print head in a certain cycle is obtained based on the detected speed of the previous cycle, if the moving speed of the print head changes relatively larger, the difference between an estimated speed and an actual speed of the print head is greater. As a result, there is a problem that if the variation in moving speed of the print head is large, the difference between a target print position and an actual print position is large.